This study investigates the incidence of post-transfusion hepatitis (PTH) in prospectively followed open-heart surgery patients following a variety of measures to interdict infectious donors. These measures have included sequential testing of donors for alanine aminotransferase (ALT), antibody to the Human Immunodeficiency Virus (anti-HIV-1), antibody to hepatitis B core antigen (anti-HBC) and antibody to the hepatitis C virus (anti-HCV) as well as intensive donor questioning in regard to high-risk behavior. Between 1985 and 1990, hepatitis incidence has fallen from 10% to approximately 3%. It is anticipated that levels will fall to between 1% and 2% following the introduction of anti-HCV testing. Evaluation of the latter is currently in progress. Greater than 95% of PTH is classified as non-A, non-B hepatitis and approximately 90% of this HCV related. Because of closure of the NIH open-heart surgery program, these studies are being conducted at Georgetown University Hospital (GUH) and Fairfax Hospital.